size = int(input('请输入需要打印的棋盘大小:'))
for i in range(size):
    for j in range(size):
        if i == 0 and j == 0:
            print('┌ ',end ='')
        elif i == 0 and j == size - 1:
            print(' ┐')
        elif i == size - 1 and j == 0:
            print('└ ',end = '')
        elif i == size - 1 and j == size - 1:
            print(' ┘',end = '')
        elif i == 0 and 0 < j < size - 1:
            print(' ┬ ',end = '')
        elif i == size - 1 and 0 < j < size - 1:
            print(' ┴ ',end = '')
        elif 0 < i < size - 1 and j == 0:
            print('├ ',end = '')
        elif 0 < i < size - 1 and j == size - 1:
            print(' ┤')
        elif 0 < i < size - 1 and 0 < j < size - 1:
            print(' ┼ ', end='')
